Return to Fluid Spheres Lesson Sequence

Coriolis effect

State Standards: GLEs/GSEs

SS1 (ext.)-3 Students demonstrate an understanding of processes and change over time within earth system by
3aa describing how interaction of wind patterns, ocean currents, and mountain ranges results in a global pattern of latitudal bands of rain, forests, and deserts.

National Standards:

Energy in Earth System
12DESS1.3 Heating of earth’s surface and atmosphere by the sun drives convection within the atmosphere and oceans, producing winds and ocean currents.

Context of Lesson:

Students will learn how to work in groups. They will be assigned different tasks (perhaps jigsawed for the future?). The idea of for each group to first come to an agreement as to how free-floating objects appear to change direction when a spinning sphere is introduced. Students will make predictions as to what will happen to a free-floating objects when effected by the circular, spinning surface.

Opportunities to Learn:

Depth of Knowledge

Prerequisite Knowledge

Students will have prior knowledge on how wind forms and where it comes from, but not how it is affected by the earth's rotation.

Plans for Differentiating Instruction

Group work is part of this lab so students can work with one another. Physical activities incorporated for kinesthetic learners.

Accommodations and modifications

Students will be assigned to groups or rearranged depending on their performance in class as teacher sees fit.

Environmental factors

Materials

Handouts on Hadley cells from pg 301/300 in EarthComm (if not handed out already)
review
http://www.mlms.logan.k12.ut.us/science/ESCoriolis.html
stopwatches
Coriolis Jobs F08 Handout
Critical Thinking Questions
Coroilis Effect Worksheet
Coriolis Lab Steps
Coriolis Jobs08 Handout Part II only


paper plates
rulers
pencils or sticksrubber bands
scissorsscotch tape
globe
saran wrap
globe
markers (red, green, purple)

Objectives:

You will be able to...

• build your own, simulated Coriolis effect model
• identify and describe the coriolis effect
• discover how movement of wind is effected by the coriolis
• give a specific example of a wind pattern created by the coriolis
• identify a specific historical example of the coriolis effect
• identify where hurricanes form (hurricane hannah)
• name the weather patterns and motions that the coriolis effects drastically
• tell someone the problem fishermen experienced in the pacific coast years ago (don’t give them answer yet-- save for next class)

Instruction:

• Have them pass in worksheet. If it was hard, review it in class.
• Did anyone get a chance to watch the clip on Indonesia last night? What did you think of it. Would you rather write about it or talk aloud?
  • Have students discuss the video.
• Today we will discover a little more about why Indonesia has their weather.
• Review last class.
  • What did the Polynesians teach us about?
    • Tradewinds exist. We know that wind blows from the equator northward, but we don't know why the wind travels in a zig zag like pattern.
  • Where does wind come from?

Opening:

• Announce that last class we left of trying to determine why the Hadley cells stop at 30 degrees N and S of the equator. Today we will find out the reason for it. We will also find out the reason for the zig zag pattern the Polynesians used to discover Hawaiian islands.
• Have students get out their notebooks.
• Tell them the story of the Paris Gun in WWI 1918 used by Germans to bomb Paris distance was 75 miles their trajectory calcuations were messed up, kept landing to the right of their target, by miles (see notes on the blue planet outline) and how missles missed their target.
• In 1914 English and Germans fighting near Falkland Islands off Argentina (10 miles away) missed their targets.
• Our goal for today is to discover what caused this missed target, as well as what causes the zig zag wind patterns near the equator and what causes hadley cells to stop?

Engagement:

• Activity 1: Discovering the reason for these changes that exist in the earth's atmosphere.

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• PART I
  • Preparing for the the Activity.
    1. Divide the class into groups of four by counting off by #students in class/four.
    2. Assign roles to the groups by passing out the following handout and having each person pick a role for each PART/activity.
    3. Write the jobs on the board
       • Coriolis Jobs F08 Handout (cut and folded)
  • Beginning the Activity
    1. Describe each job description to the class. Ask if anyone has any questions about it.
    2. The idea of this is to allow each student a turn to speak and so each person does a fair share.
    3. The questions are designed to get students thinking so it doesn’t matter if your answer is right or wrong. What's more important is that you are discussing something.
    4. ’m going to be coming around to see how this is working for the groups.
    5. Have students begin to question one another using Critical Thinking Questions
       • Questions handed to them on a sheet of paper will be.
         1. Can a person can be moving even if they are sitting very very still (breathing or blinking is not considered moving for this question)? If so, give an example. (Remind the time keeper to start timing now.)
         2. (for the next group member) An alien is watching us from outer space sitting in our chairs. If they stared at us for 24 hours straight, would we appear to be moving to them? Why or why not?
         3. (Next group member) You and your friend are at six flags and decide to ride the merry-go-round. You want to play catch with the basketball you just won. Each of you chose horses on opposite sides of the merry-go-round. Before the ride starts, you start playing catch. Then merry-go-round starts to rotate very fast. Your friend throws the basketball in your direction from across the merry-go-round. Will the basketball reach you or go somewhere else (assume there is nothing in your way that is blocking the pass and that nothing touches the ball while it is being passed).

• After allowing students to interview their peers, give them 5 minutes to talk about the questions one by one and come to a conclusion as to what they think the answer is. Don’t worry about if your answer is right or wrong.
  • Have the time keeper use the stopwatch to keep time for this portion as well.

• Then have the announcer write their conclusions on the board while I guide the discussion.

• Discussing the Activity
  • Get the class's attention.
  • Question 1 posed: What was the purpose for asking Question 1.
    • Expected Answer: Students mention a moving car or an airplane to get them thinking about the following example:
      • someone can appear stationary if in a car, but if observer is outside the car and watch friend drive away, they appear moving, so it depends where you are
  • Question 2 posed: What was the purpose for Question 2?
    • Expected Answer: Earth’s rotation exists because we are all moving even though we can’t feel it (earth rotates once in a day so we are moving along with the earth)
  • Question 3 posed: What was the purpose for Question 3?
    • Expected Answer: It deals with a combination of Question 1 and 2. Both people are moving on this vehicle and you are attached to it just like we are attached to a car by a seat belt and inertia or the earth by gravity. The ball is thrown but the ball is free-floating, so it is going to move in a straight line, but the friend is rotating on the merry go round so by the time the ball gets to the other side, friend would have moved.

• PART II
  • Divide the group up into new positons, using second folded pieces of paper found here Coriolis Jobs F08 Handout (cut and folded)
  • Does everyone understand their job?
  • Explain that on top of their positions, they are all going to take on the role of experimenters as well.
  • Hand out the following worksheet:
    • STEP 1: Your goal is to create a manually-spinning disc, (like a spinning top or a record) with a flat surface with the materials provided. Each person should create their own spinning disc.
    • STEP 2. Once the spinning disc is created, spin it between your fingers on a flat surface to ensure it has good rotation. Assign somone as the designated disc spinner.
    • STEP 3. Have another group member hold a ruler about 2 or 3 inches above the disc, parallel to the ground, to create a straight edge just as if someone was using the ruler to draw a straight line on the disc. This will guide the tracer's movement.
    • STEP 4. Now, while the group member is holding the ruler in a steady position and while the other is holding the disc stationary, have a remaining group member trace a straight line (using the ruler as a guide) onto the disc. Once your make your line, put an arrow on the end to show the direction your line was travelling.
    • Trace two more "arrows" using the ruler, onto the disc as follows...
      • once (in green) while the disc spinner steadily rotates the disc counterclockwise
      • once (in purple) while the disc spinner steadily rotates the disc clockwise
    • STEP 5: Carefully observe the path of the different colored arrows. Record whether your line came out straight or curved. If it was curved, indicate the disc rotation and if it curved to the right or to the left. (Do Not Use Counterclockwise/Clockwise to indicate the movement of the line. It will only confuse you.)
    • STEP 6: Repeat STEPS 3 through 5 until each group member's disc is marked with the three different colored lines.
    • STEP 6: As a group, sum up what happened to each of the three lines in a table below:

disc movement	color of line	shape of line	curvature
stationary
counterclockwise
clockwise

• STEP 7: Answer the following: Even though you drew the marker in a straight line each time, it created a curved path. Why?
• Describe the experiment to the class and show them where materials can be gathered. Let them know you are their if they have questions. Require outcomes to be written on the board.
• Have students gather together after experimenting and state their results. They can write it on the board so everyone can see everyone’s results.
  • STEP 8: Discuss with your group which way you think the earth rotates: Clockwise or counterclockwise. Does it depend on your location?

Closure:

• Activity 2: Discussing the results.

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• Allow 20 minutes for this.
  • Discuss student data that is written on the board.
    • Have students explain what they found.
      • Did each color marker yield the same results?
        • Does it make sense?
      • Did the marker always travel straight line?
        • Expected Answer: Yes, although since the base was moving it appeared curved.
    • Compare similarities and differences.
  • Discuss the deviations in straight lines by making a table on the board with the correct directions.

disc movement	color of line	shape of line	curvature
stationary	red	straight	none
counterclockwise	green	curved	to the right
clockwise	purple	curved	to the left

• Ask students to explain this phenomona.
• Activity 3: Relating this lab to our last lesson.

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• Question 1 posed: Can anyone guess, if you were looking at earth from outer space form the north pole, would earth be rotating counterclockwise or clockwise?
  • Have student use globe to figure it out.
    • Expected answer: counterclockwise
• Question 2 posed: Why would we use markers and discs to try to explain the phenomona we talked about at the beginning of the class?
  • What does the spinning disc represent?
    • Expected answer: the earth
  • What does the marker represent?
    • Expected Answer: wind, clouds, fluid, bird, airplane
  • Explanation: The marker helps you visualize an object floating across the surface. Since you have free moving objects that are not glued to earth, they travel in their own paths, independent of the earth, just as the marble can travel in its own path across the surface, It is not glued to the surface. the marble appears to take a curved path, but you always rolled it in a straight line. Therefore, even if an object is moving in a straight line, it appears to take a curved path because everything below it is moving!
• Question 3 posed: Does what we realized explain our merry-go-round question?
  • Expected answer:
    • Yes, because...
• Write on the board
  • the curved path of a moving body due to [ ] rotation
    • Have students fill in the parentheses with the word EARTH's
    • This is called the Coriolis Effect
      • it influences all moving bodies, including moving air, directions of all winds subject to coriolis effect
• Have them construct a graph while I write on the board this table
  

hemisphere	curves towards the	rotation
northern	right	counterclockwise
southern	left	clockwise

• Question 4 posed: Why is the coriolis effect of great importance for the Polynesians?
  • Require student to think back to hadley cells (review what we learned last class).
  • What do you know about the Hadley cells?
    • Expected answer: Wind travels towards poles, but after covering vast amount of distance, it cools and sinks creating surface winds (tradewinds).
    • Why does the air cool?
      • Expected answer: Expanding and movement creates loss in energy and a cooling, cool air is always below warmer air.
• Hand out the handout of page 301 of EarthComm.
  • Have students go back to their diagrams they drew last class on Hadley cells.
  • Describe how winds curve ot the right in the Northern hemisphere and vice versa in the Southern one.
• Ask them how influential this effect is. Does it affect our daily lives? If I throw a ball to you are you affected by it?
  • Throw a ball across the room to someone.
    • Expected answer: In truth, the coriolis force is very small (it takes earth 24 hours to rotate one complete circle and our paper plates roated about once per second. so it would not effect our marble. The only reason our marble moved was because we created a spinning surface that simulates the earth’s rotation, spins a lot faster than the earth once/second versus once/24 hours. It only affects things on a larger scale that is travelling long distances.
• Does anyone have any examples?
  • Expected answers? The shells from the paris gun, tradewinds

Assessment:

IS VERY IMPORTANT TODAY

• Question 1 posed: Was what we created the coriolis force?
  • Expected answer: No. We simulated what happens to free-moving objects on earth.
• Question 2 posed: How does Coriolis effect affect tradewinds?
  • Expected answer: It curves them just like it curved the marble.
• Question 3 posed: Is the Coriolis effect a force?
  • Expected answer: Yes
  • Actual answer: No, because...
    • No forces acted on the marble (besides some friction, just as if a ball tossed from one end of moving merry-go-round to the other has no forces acted on it). It is only because the surface of the merry-go-round, plate, earth, is moving that it appears that it appears to curve. Some people refer to it as the coriolis force, but it is not a force, it is a depeption.

• Question 4 posed: Are hurricanes affected by this force?
  • Expected Answer: Yes! it is why they rotate the way they do!
    • Hurricanes, or monsoons, are a partial reason why Indonesia suffers from droughts. There is a rainy season and a dry season. We will continue to study what else can be affecting it.

homework

Coriolis Effect worksheet
check out the possible websites
http://www.youtube.com/watch?v=8UB3mhcBXfk
http://www.youtube.com/watch?v=1mdlDEK3VmU&feature=related
[[http://www.youtube.com/watch?v=_R7L5DNvgfU&feature=related | Physics of Weather, Its a simpson’s cartoon!]]

Reflection:

(only done after lesson is enacted)
Student Work Sample 1: Approaching Proficiency
Student Work Sample 2: Proficient
Student Work Sample 3: Exceeds Proficiency